Resettable circuit breaker



Nov. 24, 194% 1.. ROSTOKER 2,302,717

RESETTABLE CIRCUIT BREAKER Filed May 27, 1949.

1 V j L Rohoker ratented Nov. 24, N42

UNITED STATES PAT al-Qn 2,302,717 RESETTABLE CIRCUIT BREAKER Louis Rostoker, Toronto, Ontario, Canada Application May 27, 1940, Serial No 337,382

(Cl. 201L416) 5 Olaims.

This invention relates to resettable circuit breakers, and the object of the invention is to devise a circuit breaker which will operate quickly and eilciently without fusing the thermal operating element or other contacts, thus increasing the eii'ective life of the device.

The invention is hereinafter described and illustrated, by way of example, in the following drawing in which Figure 1 is a side elevation of the circuit breaker;

Figure 2 a longitudinal section on the line 2-4 in Figure 1;

Figure '3 a similar view to Fig. 2 with the circuit breaker in unset position;

Figure 4 a transverse section on the line 33 in Figure 2;

Figure 5 a side elevation of one side of the core with'the shell and cap removed;

Figure 6 a plan view of the core with the shell and cap removed; and

Figure 7 a side elevation of the opposite side of the core with the shell and cap removed.

In the drawing corresponding numerals in the different figures refer to corresponding parts.

The circuit breaker is in the form of a plug provided with the usual adapted to screw into a socket (not shown) provided with circuit terminals. The shell l forms a contact member which is adapted to engage one of the circuit terminals in a socket. A core ll of insulating material fits into the shell i0 and is provided at its bottom with a base or end contact I! which is adapted to engage the other circuit terminal in the socket. The core II is provided with two slots H and I l which extend into the core past the center line thereof. The inner end of the base contact member l2 extends through the insulated core to a point adjacent the underside of the lower slot li Extending axially of the core II is a hole II in which is slidably mounted a conducting rod iii. The rod II has connected to its upper end a plunger H of hard rubber or similar insulating material which in turn has secured to the upper end thereof a knob I of insulating material. A cap II of insulating material screws over the shell II "and is secured thereto by means of a grub screw 22'. The insulating plunger [4 extends above the end of the core II and through the cap 22 and a compression spring i6 surrounds the -member I 4 and engages the knob i5 and the upper end of the cap 22 tending to force the knob away from the core, and hence to move the conducting rod l3 outwardly. An annular plate I! threaded brass shell Ill lic strip l8 will become is secured to the top of the core ii around the central hole The diameter of the hole in the plate I1 is somewhat less than the diameter of the hole H so that the plate will engage the upper end of the rod i3 when the rod i3 is urged outwardly by the spring l6, thus limiting its outward movement.

Below the upper end of is a reduced portion II which when the circuit breaker is set registers with the slot II in the core and is engaged by a iii-metallic conducting strip i8. v

The bi-metallic strip is secured to the core H by means of a screw II in the vertical groove l i The screw l9 clamps the end of the lei-metallic strip between a leaf spring support 29 and a conducting strip 21 which lies in the bottom of the groove li and which has an outwardly curved spring end part 2| which engages the shell in forming a contact therewith.

In ordinary operation the biunetallic strip it in combination with the reduced portion it of the conducting rod N forms a lamh in which the the conducting rod i3 catch member is the bi-metallic strip and the keeper-is the shoulder formed by the reduced portion I3. When the oi-metallic strip i8 is contacting with the conducting member i3 said conducting member is retained in contact with the base contact member I! as shown in Figure 2. The electrical current travels through the shell, the conducting member 2|, the iii-metallic strip l8 and the conducting rod l3 to the base contact member ii. If there is an overload the bi-metalheated and will straighten out until it disengages from the shoulder formed by the reduced portion i3. Thereupon the conducting rod II will be moved upwardly by the pressure of the spring it to the position indicated in Figure 3, en because of the fact that the conducting rod II is out of contact with the base contact member l2. It will be understood that the breaking of this contact will take place immediately that the bimetallic strip ll becomes disengaged from the conducting rod 13. There will be very little arcing, but what arcing does take place will take place at the point of contact between the conducting member I! and the contact member 12, rather than between the conducting member 53 and the bi-metallic strip IS. The slot ll forms an arc chamber which is separated by the insulating core from the point at which the bi-metallic strip ll engages the conducting member ii. To re-=set is only necessary to Dress the end or" the conducting the circuit breaker it down the knob i 5 until so that the circuit will be brokmember it engages the base contact member 12 the bi-metallic strip l8 snaps into the reoi i portion thus retaining the circuit breaker in operative position as shown in Figure 2.

What I claim as my invention is:

1. In a resettable circuit breaker, a contact member adapted to engage a circuit terminal, a second contact member adapted to enage another circuit terminal, a spring pressed conducting member insulated from the second contact member and normally not contacting the first mentioned contact member, but manually movable into contact therewith, a second conducting member connected to the second contact member and normally in electrical contact with and engaging the spring pressed conducting member to retain it in contact with the first mentioned contact member, whereby an electrical circuit may be completed between the two contact members, said second conducting member being thermally operated by overload to disengage itself from and break contact with the spring pressed conducting member to permit the latter to spring out of contact with the said first mentioned contact member thus causing a double break in the circuit.

2. In a resettable circuit breaker, a contact member adapted to engage a circuit terminal, a second contact member adapted to engage another circuit terminal, a conducting member insulated from the second contact member but adapted to contact the first mentioned contact member, spring means tending to move the conducting member out of contact, manually operable means for moving the conducting member into contact, and latch means for retaining the conducting member in contact against the spring pressure, said latch means comprising a shoulder on the conducting member and a bi-metallic conducting strip connecting the conducting member and the second contact and normally engaging and in electrical contact with the shoulder on the conducting member to retain it in contact with the first mentioned contact, said oi-metallic strip being adapted to move out of engagement with the shoulder and out of electrical contact with the conducting member when an overload passes therethrough to permit the conducting member to spring out of contact with the first mentioned contact member thus causing a double break in the circuit,

In a resettable circuit breaker, a shell contact member, a base contact member, an insulatin core member within the shell, a conducting rod slidably mounted in the core and adapted to contact the base contact member, a spring pressing the conducting rod out of contact with the base contact, and a bi-metailic conducting strip mounted on the core and electrically connected to the shell and normally engaging and in electrical contact with the conducting rod to retain it in contact with the base contact member, said bi-metallic strip being adapted to move out of engagement and contact with the rod when an overload passes therethrough to permit the rod to spring out of contact with the base contact member, thus causing a double break in the circuit.

v4. In a resettable circuit breaker, a shell contact member, a base contact member, an insulating core member within the shell having two transverse slots therein, a conducting rod slidably mounted in the core and adapted to contact the base member, a spring pressing the conducting rod out of contact with the base contact, one of the slots in the core being located opposite the point or contact of the base contact member with the conducting rod to provide an arc chamber, and a bi-metallic conducting strip mounted in the other transverse slot in the core and electrically connected to the shell and normally engaging and in electrical contact with.

the conducting rod to retain it in contact with the base contact member, said bi-metallic strip being adapted to move out of engagement and contact with the rod when an overload passes therethrough to permit the rod to spring out of contact with the base contact member, thus causing a double break in the circuit.

5. In a resettable circuit breaker, a shell contact member, a base contact member, an insulating core member within the shell, a conducting rod slidably mountecl'in the core and adapted to contact the base contact member, an insulating plunger secured to the conducting rod and extending above the core, an insulating knob at the end of the plunger, an insulating cap on the core surrounding the shank of the plunger, a spring surrounding the rod and engaging the knob and the top of the cap and pressing the conducting rod out of contact with the base contact, and a bi-metallic conducting strip mounted on the core and electrically connected to the shell and normally engaging and in electrical contact with the conducting rod to retain it in contact with the base contact member, said bimetallic strip being adapted to move out of engagement and contact with the rod when an overload passes therethrough to permit the rod to spring out of contact with the base contact member, thus causing a double break in the circult.

LOUIS ROSTOKFR. 

